File card brushes are measured according to length x width. They can be sized in millimetres or inches.
The available sizes for file card brushes are:
Length
Width
120 mm (5 inch)
40 mm (1.5 inch)
125 mm (5.5 inch)
40 mm (1.5 inch)
210 mm (8.3 inch)
25 mm (1 inch)
240 mm (9.5 inch)
40 mm (1.5 inch)
250 mm (10 inch)
40 mm (1.5 inch)
280 mm (11 inch)
40 mm (1.5 inch)
Smaller file cards should be used on small files, as this would give you more control when brushing. Larger file card brushes should be used on larger files, so when you are brushing, the file card covers a larger area of the file.
The change in lengths and widths is down to manufacturers choosing to design their file card brushes at these sizes.
